The invention relates to a seat and lid assembly for a toilet, and more particularly to such a seat and lid compromising injection molded, reinforced plastic inserts injection over-molded with a chemically compatible material which provides the desired outer surface characteristics of the seat and lid.
The invention is directed to the improvement of the feel and comfort of a toilet seat and lid, and to the provision of a comfortable, warm, non-slip seating surface. This is accomplished by utilizing modern thermoplastic material and high-pressure injection molding techniques. While not intending to be so limited, the invention will be described in its application to a toilet seat and lid. It will be understood that the basic teachings of the present invention can be applied to toilet seats without lids and other types of seats.
Prior art workers have devised many types of toilet seats and lids to improve the comfort, look and convenience thereof Heretofore toilet seats and lids have been constructed from rigid materials such as wood or plastic, or made from a solid core upholstered in foam padding and/or a vinyl covering. Typical rigid plastic or wood seats are relatively cold to the touch and slippery. Upholstered seats and lids, with or without padding, are not particularly durable and are susceptible to cuts and tears. Additionally some people find the feel of padded vinyl seats and lids to be undesirable. Prior art workers have molded a material over another material in an attempt to hide imperfections in a thick part but still produce a hard rigid seat that does not address the issues of comfort and non slip characteristics. Prior art workers have also attempted to produce a padded, resilient-type seat using complicated and costly molding methods employing catalyzed materials such as urethane. Molding a seat by using catalyzed low pressure materials requires time-consuming mixing and pouring, resulting in less than satisfactory results and a costly product.
The present invention is based upon the discovery that a seat and lid assembly comprising inserts of reinforced thermoplastic material, with over-molded thermoplastic material which determines the characteristics of the outer surface of the seat and lid, can overcome the above noted problems. There are six Shore scales that are used to measure the hardness of synthetic materials. They are as follows: Shore A, Shore B, Shore C, Shore D, Shore DO and Shore OO. All of the scales range from 0-100. The most commonly used scales are Shore A and Shore D. There is no direct conversion between the different scales. An example of an approximate comparison would be (Shore A 50=Shore B 30-35=Shore C 20=Shore D 10-15). Another example of approximate comparison would be (Shore A 100=Shore B 85=Shore C 65=Shore D 45). The preferred polypropylene material used for the insert has a hardness of approximately Shore D 70. When a thermoplastic elastomeric material with a Shore A durometer of 90 or below is used as the over-mold material, the seat and lid are provided with a soft, comfortable, durable surface which will not tear and which have non-slip characteristics, which, nevertheless, allows reasonable mobility while using the seat. The thermoplastic elastomeric material should not have a durometer hardness greater than Shore D50. Some synthetic materials have a durometer hardness that would be measured on the Shore A scale. Harder synthetic materials would be measured on the Shore D scale. The elastomer provides a completely different and arguably superior feel as compared to conventional seats and padded seats. The seat of the present invention is not padded and does not deform when sat upon. The surface also provides an aesthetically pleasing finish which is easily cleaned and is available in many colors.
It is an object of the present invention to provide an injection molded toilet seat and lid which are soft to the touch and relatively warm and non-slip as compared to a conventional hard seat and lid.
It is an object of the present invention to provide a toilet seat and lid with the above features which are both strong and durable.
It is an object of the present invention to provide a toilet seat and lid with the above features which are easy to clean.
It is an object of the present invention to provide a more comfortable and non-slip toilet seat and lid assembly, than is achievable with existing designs and conventional construction techniques.
It is an object of the present invention to provide a seat and lid with antimicrobial qualities.
Finally, it is an object of the invention to provide a soft feeling injection molded toilet seat shaped to fit the user comfortably.
According to the invention there is provided a strong, durable, comfortable toilet seat and lid assembly which is non-slip and easy to clean. The assembly comprises rigid inserts molded of a reinforced thermoplastic material. The inserts are over-molded with a thermoplastic material which provides them with the desired surface characteristics.
The inserts are precisely dimensioned so that their areas to be over-molded are smaller than the finished seat. The inserts are designed to give maximum strength to the seat and lid and are shaped to promote the flow of the over-mold material to minimize flowjoint or flow weld problems, to be described hereinafter. Each insert is designed to minimize shrinking, swelling or distortion thereof and, to this end, can be provided with strategically located ribs and appropriate cored areas.
When the thermoplastic material of the inserts and the over-mold material elastomer are both of the same chemical base, the over-mold will bond both mechanically and chemically with the inserts and will provide the seat and lid with a soft, comfortable, non-slip surface. The surface may be smooth or textured to enhance the feel and appearance of the seat.